<?php 

Class MsgStack{
  private static $ULS = "<ul>";
  private static $ULE = "</ul>";
  private static $LIS = "<li>";
  private static $LIE = "</li>";  
  
  private $message;
  public $isErr;
  
  function __construct(){
    $this->message = MsgStack::$ULS;
    $this->isErr=false;
    
  }
  
  public function getMsg(){
    return $this->message.MsgStack::$ULE;
  }
  
  public function push($msg){
    $tmp =MsgStack::$LIS.$msg.MsgStack::$LIE;    
    $this->message.=$tmp;    
  }
  
 
  
}
?>